ABSTRACT The Flow Cytometry (FC) Core offers centralized expertise and instrumentation in Flow Cytometry and Cell Sorting to investigators of the Cancer Center. The extensive user support includes a) assisting in planning, executing, and analyzing Flow Cytometry experiments; b) daily instrument setup, maintenance, quality control and performance monitoring; c) facilitating instrument access through implementation of adequate polices with an easy and reliable scheduling system; d) offering several software site licenses for high-end Flow data analysis; and e) extensive training and education options. Instrument based-services include operator-assisted cell sorting in five multiparametric FACSAria high-speed cell sorters, user-operated cell sorting in two multiparametric FACSAria cell sorters, and user-operated analysis in five high-end multiparametric analyzers (two LSRII and three LSR Fortessa) and a four-parameter FACSCalibur. Altogether, the availability of high-end instrumentation and highly qualified staff with experience provide investigators of the Center access to highly purified cell populations, and the possibility to characterize cell subsets involved in the processes of tumor development, which can ultimately lead to improved cancer diagnosis and therapy. The services provided by the FC Core have supported 239 investigators from over 140 laboratories in the last year. During the past grant period the efforts of the Core contributed to 843 publications of researchers from the 10 Programs. As an illustration of this support, a recent collaborative study among the laboratories of Drs. Sadelain (ET,CR), van den Brink (IT,CR), and Schietinger (IT) was facilitated by the Core?s expertise and instrumentation provided to analyze immunophenotypic markers in T cells, phopho-flow to analyze T cell signal transduction pathways, as well as state-of-the-art sorting services to isolate GFP-labeled CAR T cells from mouse transplants that were subsequently subjected to transcriptome profiling. The resulting publication of this study provides insight into mechanisms of allogeneic CD19 CAR T cells promoting anti-tumor activity in lymphomas.